Unit Testing With SilverStripe

PHPUnit talk hold at the SilverStripe Conference 2017 in Malta. See www.stripecon.eu

Transcript

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2. What Is Testing?
   • A piece of code that tests your code
   • A scenario how your code should work
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3. Why Should I Test?
   • It‘s fun!
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4. Why Should I Test?
   • Don‘t we already test our code?
   • F5-Driven Development
   – Feedback Loop (var dump etc…)
   • Pray on deployment
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5. Why Should I Test Automatically
   • A computer is good in processing things
   over and over again
   • Without complaining
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6. Quotes
   • Tests for a project mean that at least
   somebody used to care at some point about
   what they were doing (Chris Hartjes)
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7. Quotes
   • Testing your code requires you to change
   how you write code (Chris Hartjes)
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8. Quotes
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9. Quotes
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10. Quotes
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11. BUT…
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12. Contra Testing
    • Writing tests takes more time
    • You have to reason about what you‘re
    doing
    • It‘s not easy to write good and meaningful
    tests
    • No 100% guarantee that your code is bug
    free
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13. Contra Testing #2
    • Running them takes a long time
    (DB connection is slow)
    • I‘m the only one in the company that runs
    my tests
    • You have to change your habbits
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14. Pro Testing
    • It‘s just code – and we know how to code
    • Repeatable – don‘t throw away your
    (manual) tests
    • Future investment
    • 90% less bugs in production
    • Bugs are found during development phase,
    not after shipping
    – That‘s cheaper
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15. Pro Testing #2
    • Makes you reason about your code
    – Structure
    – How the code should solve the given problem
    • Documentation of how your code is
    supposed to work
    • Makes you a better developer
    • Refactoring becomes easier
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16. ANATOMY OF A TEST
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17. How Does A Test Work?
    • Arrange
    • Act
    • Assert
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18. Arrange
    • Get your prerequisites
    • Identify dependencies
    • Fixtures, Mocks…
    • Define the expected result
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19. Act
    • Call the method you test
    • and grab the result
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20. Assert
    • Compare your result or behaviour
    with the expectation
    • Throw a meaningful message on failure
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21. Types Of Tests
    • Unit tests
    – Small units of your code, usually a method
    • Component tests
    – Bigger unit,
    – might use database
    – takes longer to run
    • Functional test
    – End to end, incl. GET / POST request etc..
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22. WHAT IS
    „TEST DRIVEN DEVELOPMENT“?
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23. Test Driven Development (TDD)
    • Write your test first
    • Run that test
    – Watch it failing
    • Write code to fulfill your test
    • Run the test again
    – Watch it passing
    • Refactor your code
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24. Red – Green - Refactor
    Write a
    failing
    test
    Make
    that test
    pass
    Clean
    up your
    code
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25. TDD Workflow
    • Make it work
    • Make it right
    • Make it fast
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26. TDD Pro
    • Fast Feedback loop with small iterations
    • Design your code in a testable manner
    • More modular
    • Cleaner interfaces
    • „Stupid“ mistakes are found immediately
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27. LET‘S PLAY!
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28. What Should I Test?
    • Expected results
    • Return types
    • Error handling
    • Thrown Exceptions
    • Etc…
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29. Start Writing Tests
    • A new module is a good start
    • Legacy code is no excuse
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30. Testing A Legacy Project
    • Code might be harder to test
    • You have to reason about the existing code
    • Tests create a backlog for technical debt
    – Technial debt is a bad thing that backfires.
    Always
    • Proof that legacy code works – or not
    • A safeguard for refactoring
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31. PHPUNIT
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32. PHPUnit
    • Written by Sebastian Bergmann
    • Since 2004
    • Instance of xUnit architecture
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33. PHPUnit Conventions
    • Naming:
    – Class Email
    – Test class: EmailTest
    • A test method starts with „test“, e.g.
    testEmailSentWhenNewUserRegisters()
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34. PHPUnit & SilverStripe
    • Tests subclass SapphireTest
    • Provides yml Fixtures
    • Custom assertions for SilverStripe
    • Switch to test without fixtures / db setup
    (SilverStripe 3.5+)
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35. SilverStripe Specific Assertions
    • assertEmailSentTo
    • assertSQLContains …
    • assertDOSContains (assertListContains)
    • assertDOSEquals (assertListEquals)
    • assertDOSAllMatch (assertListAllMatch)
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36. PHPUNIT GOODIES
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37. Data Providers
    • Write more generic tests, feed different
    data to it
    • You can reuse them, also call from different
    classes
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38. Before
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39. After
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41. Order Of Tests
    • @depends
    • TODO: Code example
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42. Test As Documentation
    • --testdox
    – Automatic generated documentation from test
    names (or annotation)
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43. testdox
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44. Debug a Unit Test
    • Combine the strength of two power tools
    • Needs CLI-Debugging configured
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45. Further Resources
    https://leahttps://leanpub.com/u/chartjesb.c
    om/u/chartjes
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    https://leanpub.com/u/chartjes
    

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46. About me
    • Werner M. Krauß
    • Located in Hallstatt, Austria
    • wmk on IRC slack / github / stackoverflow
    • PHP since 1998
    • Freelancer since 2006 (netwerkstatt)
    • SilverStripe since 2009
    

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47. Thank you!
    www.silverstrip.es
    

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